الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Injuries to the foot and ankle are often missed or underestimated during the initial care for poly-traumatized patients. Since the mortality of trauma decreased in the last decades, injuries to the lower extremity exert significant influence on long-term outcome after discharge from the acute care facility.
Radiography often underestimates the extent of injury and degree of displacement of fracture fragments in the extremities. MDCT in the extremities is helpful in fracture detection, evaluation, characterization, and treatment planning. Complex intra-articular fractures of the extremities can also be evaluated thoroughly.
Extremity imaging has benefited tremendously from advanced MDCT. The ability to scan once and generate oblique images in any plane with no loss of resolution is the key for high-quality extremity evaluation. It is no longer necessary to position patients who are already in pain into uncomfortable positions in order to obtain diagnostic images.
MDCT allows for scanning through full plaster casts or back-slabs. The image quality is improved, as the patients are more comfortable and they lie still for the duration of the examination. When MPR and 3D VR images are required, it is a simple task to “cut away” the cast using the scalpel tool at the workstation.
The present work included forty patients, compromising 34 males and 6 females, ranging in age from 13 to 65 years with a mean age of 35 years. All patients were recommended for CT evaluation after being examined by a plain X-ray to further evaluate already diagnosed, or exclude ankle and hind foot osseous injuries.
The aim of the work was directed to evaluate the role of MDCT in evaluation of osseous injuries of the ankle and hind foot.
All patients were examined using 6 and 16 multi-detector CT scanners – Siemens’ Emotion 6 and Philips 16 – respectively. Scanning parameters were: 150 mAs, 120 KVP, 0.8 s/rot., 1 mm slice thickness and 0.5 mm reconstruction increment for Siemens while for Philips these were: 250 mAs, 120 KVP, tube rotation time of 0.6 s/rot., 2 mm slice thickness and 1 mm reconstruction increment. The thin slices were sent to the workstation, after reconstruction of the raw data using sharp bony (B70) and smooth soft tissue reconstruction algorithms (B30), where they were available to view in axial, sagittal and coronal planes. Volume rendering techniques were displayed in all patients for further clarification and for planning for surgical interference.
In our patient population, the two main injury mechanisms were falling from a height (24 patients [60%]) and a traffic accident (16 patients [40%]).
A total of 53 fractures were found in all three anatomic regions: ankle, calcaneus and talus. Of the 40 patients, 7 patients presented with bilateral ankle &/or hind foot injuries. Fractures involving more than on anatomic region was identified in 6 of the examined feet.
The present study included 9 ankle fractures, 7 talar fractures, and 37 calcaneal fractures.
Six patients (15%) had multiple fractures of the ankle and hind foot. Of which three patients (7.5%) had ankle and calcaneal fractures, two patients (5%) had calcaneal and talar fractures and one patient (2.5%) had ankle and talar fractures.
Of the studied 9 ankle fractures, 7 fractures were unstable. Instability was attributed in one patient to fractures involving both sides of the ankle mortise causing the ring to be broken in two places. Another patient showed fibular fracture on a side and deltoid ligament injury on the other side, causing the ring also to be broken in two places. One presented with dislocated ankle. Four patients presented with intra-articular distal tibial fracture (Pilon fracture).
MPR examination of the ankle tendons was done in all patients with volume rendering images of the ankle tendons displayed in all to assess possible tendinous injuries related to the fracture fragments. Thickening of the tibialis posterior and peroneal tendons was identified in two cases in the MPR images and was confirmed in the 3D image, which suggested underlying tendinous injury. Volume rendered images of the ankle tendons revealed well the anterior dislocation of the peroneal tendons accompanying ankle dislocation in one case.
Thirty one patients had calcaneal fractures (77.5%), of them six patients (19.3%) presented with bilateral calcaneal fractures.
Of these 31 patients, falling form height was the mechanism of injury in 23 patients (74.2%), while traffic accidents were the mechanism of injury in 8 patients (25.8%)
There were thirty seven calcaneal fractures, of them five were extra-articular (13.5%) and thirty two were intra-articular (86.5%) classified as Sanders type I in 4 cases (10.8 %), Sanders type II in 8 cases (21.6%), Sanders type III in 11 cases (29.7%) and Sanders type IV in 9 cases ( 24.4%).
Classification was done on basis of axial and coronal images oriented parallel to the posterior facet of the sub-talar joint as shown on the sagittal MPR image.
Of the 37 feet showing calcaneal fractures, calcaneo-cuboid joint involvement was present in twenty five feet accounting for 67.6 %, of which 23 feet (92%) showed intra-articular and 2 feet (8%) showed extra-articular calcaneal fractures.
Calcaneo-cuboid joint involvement was best identified in the axial image with adequate depiction of the degree of articular incongruity if any, which has a significant influence on the long term outcome of fracture healing.
Dislocation of posterior subtalar joint was present in one foot showing calcaneal fracture (2.7%).This was associated with comminuted fracture and splitting of the calcaneus into antero-lateral and postero-medial fragments.
The present study included seven patients constituting 17.5% presented with talar fractures, of which three fractures involved the talar neck, two fractures involved the body (with associated fracture of the posterior process in one of them) and two fractures involved the lateral process.
Articular involvement of the fractures was identified in 5 out of 7 patients with one patient presenting with talar neck fracture showing subtalar dislocation, without intra-articular extension of the fracture, though axial displacement of the bony fragments.
Of the seven talar fractures ankle joint involvement was present in four patients and subtalar joint involvement was present in five patients while none of them showed talo-navicular joint involvement.
Of the three talar neck fractures, involvement of the subtalar joint was present in only one patient (Hawkin’s type 2) while none of the three cases showed ankle or talo-navicular joint involvement with the other two patients classified as Hawkins’s type 1.
Our study included two patients with lateral process fractures, both showing intra-articular extension.
Only one patient presented with posterior process fracture, with associated fracture of the talar body.
Routine fractures of the ankle do not require CT. It is recommended in patients showing only fibular fracture with no associated medial malleolar fracture, provided that the fibular fracture is at or above the level of the syndesmosis. MDCT in these cases may be of help in detection of radigraphically occult ligamentous injury.
In complex intra-articular distal tibial, calcaneal and talar fractures, MDCT demonstrates well the degree of articular surface depression, fragment size and position. Data obtained by from volume-rendered imaging may assist the clinician in planning the surgical approach.
Computed tomography is valuable in the diagnosis of cases of occult syndesmotic injury, especially when the patient cannot tolerate stress radiographs.
Peroneal tendon dislocation is easily recognized with the 3D volume-rendered MDCT. Yet, it has not been validated for the evaluation of tendinopathy.